Track-belt supporting and tightening mechanism



G. R. PENNINGTON AND S. K. WELLMAN. TRACK BELT SUPPORTING AND TIGHTENING MECHANISM.

APPLICATION FILED NOV. I3. I919.

2 SHEETS-SHEET l- Patented Feb. 15,1921.

G. R. PENNINGTON AND S. K. WELLMAN. TRACK BELT SUPPORTING AND TIGHTENING MECHANISM.

APPLICATION FILED NOV. 13, I919- Patented Feb. 15, 1921.

2 SHEET$SHEET 2.

En venfforzs,

unrrso fems PATENT. OFFICE.

eon-non n. rmzizmcron, or CLEVELAND, um summ. x. warming, or j.

- m1) nmcn'rs, oaro;

annex-nati- 'surroa'rme Ann 'rren'rmrme irncnnmsx.

which the following is a full, clear, and'exact' description;

The objects of this in\*ention are to automatically "maintain substantial uniformity endless track .belt of in the tightness of the and also to properly a track laying vehicle, support the upper reach in use.

, The invention consists in the construction and combination of parts shown in the drawing, hereinafter described and definitely pointed out in the appended claims.

In the drawings, Figure 1 1s a plan view of so much of a track laying tractor having the invention applied to both sides thereof as is necessar to disclose the invention; Fig. 2 is a si e elevation of the invention, andFig. 3 is a longitudinal section of the link of automatically variable length, Iv vhicli 1g. is a detached perspective view of the lever 20.

Referring to the parts by reference characters,10--1O represent the two spaced apart side members of the rigid main frame of the vehicle. 12 represents the rear sprocket wheel which is rotatably supported upon the main and this is frame, and may be the sprocket wheel by which the movement of the track belt 1s produced when the invention is applied to atractor. 14 represents the front track wheel which is preferably a grooved idler wheel; likewise rotatably' supported upon the main frame, through means which will be explained. These two wheels respectively lie within the end loops of the endless track belt 15 which may be of any ordinary or suitable-constructmn. 16 represents the,

load supporting track wheels which roll on the ground reach of the track belt. The drawing does not show any load supporting connections-- between these-wheels and the main frame, because they have no relation to the present invention, and because any Specification of mm: mm,

of said track belt,

I I at which the stub ax e 17 is secured. under the varying conditisns WlllCh 81158 Patented Feb. 15, 192.1.

- Application filed Kovember 1:, 1m. ser'ial no. aawjzoa.

l suitable connections may be employed, as, for

example, such as are disclosed 1n my copIending apphcation Serial No. 337,708,.filed ov-.13,1919. The parts referred to, as shown, are .duplicated on both'sides of-the main frame, but they and the associated mechanisms to be resently described act independently.

he front idler 14 is rotatably mounted on a stub axle 17 carried by and projecting outward from a bent lever 20, which lever at its rear end is rotatably mounted upon a stud 21 carried b a bracket 22 fixed to the main frame. rom the'pivot stud 21 this lever extends upward and forward at an anglesubstantiall as shown to the oint rom this point this lever extends in a substantially vertical direction. The lever as shown is made with two spaced apart side bars, and these two side bars are connected about midway of its ends by a crossbar 23. .In the construction shown this crossbar 1s tubular. and the inner end of the stub axle 17 goes through and is rigidly secured in sald cross bar. A leaf spr1ng 19 is secured at its rear end to a bracket 11 fixed to the side frame member 10. The spring extends forward therefrom, passing between the two side bars of the lever 20 and engages and constantly bears down upon the cross bar 23. The effect of this spring is to swing the lever 20 downwardly and thereby carrythe idler 14 forward so as to increase the distance between the axis of said idler and the axis of the sprocket 12, thereby taking up suitable distance apart to the side frame member 10, and extend forwardly and upwardly at substantially the angle shown from said pivotal connections. At their upper ends these two levers 33, 34;, are pivotally. connected with the frame, 30.

I A link 40 is pivoted to the upper extension of. the lever 20 and to the lever 34 at a suitable point between the ends of the lat.- ter. This link 40 is able length, being composed of two telescoping parts 41, 42, and a spring 43 which parts in the distended position and ieldingly resists the shortenin of the lin ,but nevertheless permits the lin to shorten when an extraordinary strain is put upon it.

In the particular construction shown the part 41 telescopes into the part 42. A collar 41 on the inner end 0 the part 41 is provided for engagement with the internal annular shoulder 42 on the part 42 to limit the extension of the link.

The coiled spring 43 surrounds the two members 41, 42, and is compressed between a collar 43 which screws onto the part 42 and a collar 45 on the part 41. This spring. by

thrusting against these collars causes the engagement of the collar 41 It should be understood that this specific construction of the link is not material. In fact, the primary invention does not require that the link be of automatic variable length. The latter characteristics are, however, distinct practical advantage, and are therefore desirable, and the specific construction shown and described is a thoroughly practical construction for the purpose.

The described mechanism operates under different conditionsas followsz,

hen, as the vehicle is moving forward,

the front part of the track belt comes into contact with a rock orlog or some decided elevation in the ground, the front idler will swing upward and rearward, and the incidental shock will be largely absorbed by the spring 19. This will slacken the track belt. Under these conditions the frame 30 will be moved upwardly because of the swingin movement of the lever 20; and in its upwar movement the frame 30 will take up slack in and properly support the upper reach of the track belt. Under these conditions the link 40 will not be substantially shortened because the tension on the spring the tendency to be to it than is involved in swlnging the frame 30 upward as stated.

ut in case the pockets in the links get full, of mud or the like, or in case a stone ness is put into the track belt and thereof automatically ,variwith the shoul-.

' and hen no greater strain is applied.

foreit is not desirable, and generally it is not even possible for the frame'30 to swing upward. Under such conditions-the spring 43 of the link 40 yields and permits the link to automatlcally shorten as much as is necessary under the circumstances.

t is obvious that numerous changes may made in the specific embodiment of the invention shown without invention, providing means stated in any of Y the equivalentsof,

the following claims or such stated means be employed.

Having described our 'invention, we claim 1. In a track laying vehicle, the combina-,

tion with a main frame, an endless track belt, a sprocket wheel rotatably supported ing upward and forward from 1ts pivot and having in front of its pivot an axle on which the front track wheel is rotatably mounted, a springengaging said lever acting to swing the free end thereof downward.

2. In a track laying vehicle, the combination with a main frame, an endless track belt, a driving sprocket rotatably supported by the main rame within the rear end loop 'of the track belt, a front track wheel located. within the front loop of the track belt, a

lever pivoted to the main-frame and extending upward and forward from its pivot and aving in front of its pivot an axle on which the front track wheel is rotatably mounted, and a leaf spring secured at its rear end to the. main frame and engaging said lever and acting to swing the free end thereof downward. f

3. In a. track laying vehicle, the combination with a main supporting frame located below the-upper reach of the trackbelt, mounted on said frame the u per reach of said whicli one or more rollers for engagement with track belt, two levers are pivotally connected with the main frame, an endless track belt, a sprocket wheel rotatably supported departure-from thev main frame and extendframe and with said track supporting frame,

and a link connecting one of said levers with the lever in which) the track wheel is supported.

'4. In a track laying vehicle, the combination with a main rame, an endless track belt, a, sprocket wheel rotatably su ported by the main frame within the rear loop of the track belt, a front track wheel located within the front loop of the track belt, a lever pivoted to the main frame and extended upward and forward from its pivot and having in front of its pivot an axle on which the front track wheel is rotatably supported, a spring engaging said lever acting to swing the free end thereof downward, a track supporting frame located below the upper reach of the track belt, one or more rollers mounted on said frame for engage ment with the upper reach of said track belt, two levers which are pivotally connected with the main frame and with said track supporting frame, in one of said levers and a link connect- 15 with the lever in yieldingly resisting that of said parts which will shorten the link.

In testimony whereof, we hereunto afli our signatures.

GORDON R. PENNINGTON. SAMUEL K. WELLMflN.

endwise movement 20 

